In modern chip architectures, and in response to the growing requirements for efficient power consumption, a novel concept of “green power supply on chip” has been introduced.
Each component of a chip, for example each core, may operate in particular frequency and voltage ranges. Generally, the maximal operation frequency of circuits, and specifically CMOS circuits, increases as their supply voltage increases within the working range. On the other hand, their energy consumption is generally proportional to the square of the voltage. Thus, it is required to balance between performance requirements and power supply requirements.
Green power supply may refer in some aspects to per-core adjustment of power supply by dynamic voltage/frequency scaling (DVFS), thus using just enough power to enable each core to perform in accordance with its own requirements, and saving on the total power consumed on chip.
However, providing green power supply for a chip is a complicated problem. Some known methods make use of Buck Converters for regulating the voltage. Buck converters may potentially be highly efficient, and their duty cycle can set an arbitrary voltage conversion ratio. One challenge in building an efficient Buck Converter is the need for a small but highly efficient inductor which is an essential component of the converter. The inductor should have high quality factor (Q) and high inductance (L) density (inductance per area), at frequency range of 100-500 MHz which is the relevant frequency range. Thus, it may be required to reduce the size of the inductors and transformers, which normally occupy a significant fraction, for example about 30%, of the volume of the power converters. It will be appreciated that as the required frequencies are higher, the switching rate of the Buck Converter is required to be faster, and smaller inductors may be used.